There are six members of the family Corvidae found in Australia: five native breeding species and one infrequent self-introduction. Three are called crows and three ravens, although there is really little difference. Most Australian species are similar in size and colouration, and can be difficult to tell apart. In some cases, identification is aided by the separate ranges of different species, but differences in plumage, habits and calls offer good clues for distinguishing them. The bases of the feathers of the crows are white, while those of the ravens are grey, although this is only useful if birds are held in the hand or if discarded feathers are found.